1. Field of the Invention
The present invention relates to a battery system such as a lithium polymer secondary battery, and more specifically, to a battery system excellent in controllability for temperature thereof.
2. Description of the Related Art
In order to decrease a load to the global environment and an influence to the global warming, interest in an electric vehicle or a hybrid vehicle has been enhanced. As a power supply of such a vehicle, a demand for a high-performance secondary battery has been increased.
As such a secondary battery for the electric vehicle or the hybrid vehicle, a lithium ion battery, a nickel hydrogen battery or the like has been proposed in consideration for energy density, a lifetime, an output and the like. In a high output type of the secondary battery described above, an output of 800 W/kg or more is obtained at room temperature.